Locomotive throttle valve



F. H. "CLARK ET AL LOCOMOTIVE PHRO'ITLE VALVE June 22 ,1926. 1,589,368

Filed June 15 1925 3 Sheets-Sheet 1 j)??? in M X/Z 152/4 I June 22 1926. 1,589,368

F. H. CLARK ET AL LOCOMOTIVE THROTTLE VALVE Filed June 15. 1925 3 Sheets-Sheet 2 IIIIIIXI -IIIIIIIIII\ WITNESSES ENTORS Mz/A 9,,

June '22 1926. 1,589,368

' F. H. CLARK ET AL LOCOMOTIVE THROTTLE VALVE Filed June 15, 1925 s Sheets-Sheet s Patented June 22, 1926.

' UNITED STATES PATENT OFFICE.

FRANK H. CLARK, OF NEW YORK, N. Y,, AND ALBERT F. STEUBING, OF EAST ORANGE,

NEW JERSEY.

LOCOMOTIVE THROTTLE VALVE.

Application filed June 15,1925. Serial No. 37,281.

Our invention relates to valves for controlling the flow of steam from the bollers of locomotive engines to the cylinders thereof, and is more particularly designed for application in locomotives operating with superheated steam. The object of our invention is to provide a throttle valve, interposed between the superheater and the distribution valve chests of a locomotive, which will be easily operable, irrespective of the pressure of the steam which it controls, and will be unaffected by the expansion and contraction resultant upon the variations of temperature to which valves of this general type are necessarily; subjected. Further objects of our invention are to avoid the use of packing and glands in the operating connections, and provide a simple and positive means of adjustment, and also to provide a construction in which the members of the valve structure will be readily accessible.

The improvement claimed is hereinafter fully set forth.

Designs of throttle valves for use with superheated steam, which have been proposed in prior practice, have proven unsatisfactory, by reason'of leakage past the valves, and of unduly rapid wear. Difficulty has also been experienced in preventing leakage at the entrance of the operating mechanism into the valve casing, the connection being made, in most instances, by a sliding rod, fitted with compressible packing, held in a cavity by a gland. The objections referred to, as well as others obtaining in practice, have been found to be obviated by the application of our invention.

In the accompanying drawings: Figure 1 is a plan view of the steam connections located in a locomotive boiler smoke box, illustrating an application of our invention; Fig. 2, a vertical central section through the smoke box and throttle valve chest, with the throttle valve and its accessories removed; Fig. 3, a plan or top view of the throttle valve chest; Fig. 4, a vertical section through the same on the line 4, 4 of Fig. 3; Fig. 4, a horizontal section, on an enlarged scale, of the seat ring, looking upward; Fig. 5, a view, in elevation, of the throttle valve stem; Fig. 6, a view, partly in elevation, and partly in section, of the same taken at a right angle to Fig. 5;

and, Fig. 7, a' vertical transverse section through the cap -of the throttle valve chamber, taken on the axial line of the operating shaft.

In the practice of our invention, referring descriptively to the specific embodiment thereof which is herein exemplified, we provide a single seated poppet main throttle valve, 1, having a conical face, 1, adapted to fit against a -similarly coned face on-a seat ring, 2, which is fitted in a throttle valve chamber or chest, 3, supported in the smoke box, 4*, of a locomotive boiler, 4, between the stack, 4 thereof, and the smoke box front. The throttle valve is fitted freely on a stem, l so as to be capable of rotatory movement relatively thereto. The superheater header, 5, which may be of any suitable and preferred type, is, as in ordinary practice, located in the smoke box,'adjacent to the top of the front flue sheet, 4, and receives its supply of saturated steam from the boiler, through the dry pipe, 4 The superheated compartment of the header delivers superheated steam, through lateral steam supply pipes, 5, to inlets, 3, on the sides of the throttle valve chest, 3. The throttle valve, 1, con trols communication, through the chest, between said inlets, 3 and outlets, 3 on the chest, to which are connected the steam delivery pipes, 6, through which, when the throttle valve steam is delivered to the steam distribution valves of the locomotive.

The seat ring, 2, is, as before stated, conically faced, at. its top, in correspondence with the seating face of the throttle valve, and, below its top, is shouldered to present a flat face, which rests on a transverse partition, 3, in the throttle chest, which separates the inlets, 3*, thereof, from the outlets, 3". A balancing chamber, 3, is formed in the throttle chest, below, and concentric with, the seat ring, and a balancing piston, 7, is fitted, with the capacity of vertical movement, therein. The area of the balancing piston is slightly greater than that of the main valve at its seat.

The outer diameter of the seat ring, 2, below its flat seat, is less than that of the bore in which it sits. This clearance permits the seat ring, which, to permit complete freedom of movement, is not attached to its support, to adjust itself laterally, and

is unseated, superheated.

prevents binding of the balancing piston in its chamber, even though the heat and pressure to which the parts are subjected, should cause distortion in the valve chest. The seat ring is of relatively small cross section, and

it in place when the main throttle valve is 'unseated, and is sufficient to spring it out of its original shape, and cause its flat and conical faces to assume the contour of the corresponding seats on the valve chest and the main throttle valve, thereby ensuring that the main throttle valve will always be steam tight when seated. To prevent displacement of the seat ring from its normal location in the valve chest, it is provided with a plurality of downwardly extending guide lugs, 2, of greater depth than the maximum lift of the throttle valve, so that the seat ring cannot accidentally rise out of the bore of the partition in the valve chest in which it is seated.

The balancing piston, 7, which is provided with a packing rlng, 7, is fitted in the open topped balancing chamber, 3 at such distance below the seat ring as to afford free passage, above and around it, for steam which passes the main throttle valve, to the distribution valve chest delivery pipes, 6.

Equilibrium of pressure on the opposite sides of the normally unbalanced main throttle valve, is established, when it is desired to unseat said valve, by the preliminary movement of a balancing or pilot valve, 8, fixed on the stem, 1", of the main throttle valve, and controlling a passage for steam, through said valve, into the balancing chamber, 3 which is open to its lower side. The

preliminary movement of the stem, 1*, unseats the pilot valve, without acting on the main valve, and balances the latter by the admission of steam to the balancing chamber. The succeeding upward traverse of the stem, unseats the main valve to the degree desired.

A relief port, 7*, which is preferably formed in the balancing piston, permits the discharge of steam from the balancing chamber, intowhich steam will continue to flow. past the pilot valve, until the quantity of steam entering the chamber equals that Howing out of it. Under this condition the pressure in the balancing chamber will be slightly less than that above the main valve. If the opening past the pilot valve and the relief port, leading out of the balancing chamber, are of definite size, a constant pressure will be set up in the balancing chamber,

when the pilot valve is unseated, this pressure depending upon the pressure above the main valve. By making the area of the bail ancing piston greater than the area of the main valve, at its seat, the upward force due to the pressure below the balancing piston, can be made equal to the downward force due to the pressure on the upper side of the piston, and by thus proportioning these ports, the steam pressure will offer no resistance to the movement of the main valve, after the pilot valve has been unseated. When the valve is closed by a downward movement of the pilot valve, the steam in the balancing chamber escapes through the relief port If the locomotive is moving rapidly, the pressure below the main valve will decrease very rapidly, because of the small volume of the steam space between the throttle valve and the cylinders, and the pressure on the top of the valve will act to bring it down forcibly against the seat ring. If the valve tends to close more rapidly than the steam can escape, the steam in the balancing chamber will be compressed, and will oppose the downward movement, thus protecting the main valve from the effects of unduly rapid closure.

In order to provide for easy adjustment of the pilot valve, and also to permit the parts to be inserted in the valve chest, without being assembled, and to facilitate inspection, the pilot valve and stem are constructed so that the lift of the .pilot valve can be adjusted readily, when the parts are assembled, and in place in the valve chest. This adjustment is maintained by interlocking of the parts, when the valve structure is fully assembled. In the preferred con struction shown in Figs. 5 and 6, the valve stem, 1*, which is provided with a clevis, 1", at its upper end, for connection to the operating mechanism, is externally threaded at its lower end, for engagement by an ad justingnut, l, of squared section. A sleeve 1, preferably of Monel metal, is screwed on the stem, below the clevis, and is held in place by a rivet, 1.. A washer, 1 serves to make a tight joint between the clevis and the sleeve. The squared section adjusting nut passes through a similarly squared passage at the bottom of the valve chest, and consequently, while therein, cannot be rotated. By rotating the pilot valve, the adjustment can be varied as desired, and when the proper lift of the pilot valve has been secured, the link, 9, by which the stem is con-- nected to the operating mechanism, may be coupled to the clevis, thereby locking the parts in their proper relative positions.

It is a well recognized fact that valves that are free to move in a rotary direction, relatively to the surfaces on which they seat, remain tight for much longer periods than those that are maintained in fixed axial re.-

lation'thereto. It is also a fact that when steam enters the valve chest as a jet, the reaction of the jet against the wings of the valve, tends to s in it rapidly, causing undesirable wear 0 the valve and contacting parts. In order to oppose rotation of the throttle valve, an annular .bafile, 10, is cast on the partition, 3, of the valve chest, surrounding the valve at a proper distance therefrom, to prevent direct impingement of incoming steam against the guide wings of the valve. a a

The unseating and seating movements of the main throttle valve and pilot valve, in proper sequence, are effected, as desired, by movements, about its axial line, of an operating shaft, which is journalled in a detachable cap, 11, which covers the top of the valve chest, 3, andv is itself closed at top by a cover plate, 11. The operating shaft comprises an inner section, 12, which is mounted .in bearings in'the cap, 11, and an outer section, 12, connected to the inner section by a clutch, 12", which permits longi tudinal movement of the outer section, relatively to the inner section, while maintaining the sections in engagement for move ment about their common axial line. The outer section, 12, is journalled, adjacent to each of its ends, in a bracket, 13, bolted to the cap, 11, and carries an arm, 12, which is 'coupled to any suitable known means extending to the cab of the'locomotive, for rocking the sections, 12 and 12, in their bearings. A helical spring, 14, enclosed in a casing, 11, formed on one side of the cap, 11, bears on the bottom of said casing and, on a washer, 1'2,.on the outer shaft section, 12, and maintains a tight joint between said section and the bracket, 13, thereby preventing leakage from the cap, without necessitating the application of the ordinary gland and packing.

An arm, 12 on the inner section, is coupled to thevalve stem, 1", by the link, 9.

We claim as our invention and desire to secure by Letters Patent:

1. The combination of a throttle valve chest, having inlet and outlet passages; and

a seat ring, of comparatively small cross section, having a flange with a Hat face, resting, without positive connection, on a partition in the chest, interposed between the inlet and outlet passages thereof, and a bevelled face on the flange formin a valve seat, the outer diameter, below the auge of said seat ring,

being less than the bore of the partition in- 1 which it is fitted; and guide lugs on the seat ring, for preventin its displacement from the bore of the partition.

2. The combination of a throttle valve chest, having inlet and outlet assages; a throttle valve, seating on a. partition in the chest, interposed between said passages; a

stem, on whichthe throttle valve is fitted, with'the capacity of relative rotatory movement; and a baflle, interposed between the throttle valve and the walls of the inlet passage.

3. The combination of a throttle valve chest, having inlet and outlet passages, a throttle valve, seating on a partition 1n the chest, inter osed between said passages; a stem, on w ich the throttle valve is fitted,

with the capacity of relative rotatory motion; and an annular baflie, formed on the 

